Rare earth magnets (especially permanent magnets) typically exemplified by Nd—Fe—B magnets exhibit very high magnetic properties. Since the use of rare earth magnets can realize downsizing, output power enhancement, density enhancement, environmental burden reduction and the like of electromagnetic devices and electric motors, application of rare earth magnets is being investigated in a wide range of fields. However, in order to achieve practical application, it is requested that good magnetic properties of rare earth magnets are exhibited stably for a long time even under severe environments. Therefore, research and development are actively conducted to enhance corrosion resistance (demagnetization resistance), coercivity and the like of rare earth magnets while maintaining or improving high residual magnetic flux density. Descriptions relating to these researches are disclosed, for example, in the following literature.